Quote:
Originally Posted by fp1529
I have a 99 Suburban 1500 5.7 with 160,000 miles, original fuel pump. Yesterday the truck would not start and I realized I did not hear the fuel pump. I tried to crank it today and it fired up, I could hear the fuel pump. When the fuel pump goes is it sporadic? Could it be the pump relay?
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Fuel pumps fail in several different ways.
When key fist turned to on you VCM sends a 2 second ground prime up signal to fuel pump relay to turn on fuel pump.
To test relay check for the key on prime up signal or engine cranking fuel pump relay ground signal.
Or some just switch out relay with a known good relay.